Various devices have been developed to provide for the nasal delivery of treatment agents, such as medications or vaccines, to a subject. In the delivery of some treatment agents, such as vaccines, it is desirable to direct the treatment agent to the nasal mucosal passages while, at the same time, minimizing deposition of the treatment agent in the lower respiratory tract. However, conventional nasal delivery devices generally exhibit a number of drawbacks.
Such drawbacks can include, for example, a requirement that a portion of the device directly contact the subject's mouth. If the delivery device directly contacts the mouth of the subject, the device can become contaminated and it cannot be used with other subjects unless certain procedures or steps are taken to sterilize the device after use. Other drawbacks of conventional delivery devices can include the failure to deliver the dosage at the right time, such as during an exhalation or while a subject is holding his or her breath. In addition, conventional delivery devices are difficult to aim, causing misalignment with the nasal passages of the subject's nose and reducing the amount of treatment agent that is delivered at the desired treatment areas in the nose.